Some actuators that drive a driven body use a wire formed of a shape-memory alloy. This kind of actuator uses a principle of restoring the remembered length when the temperature of the wire formed of the shape-memory alloy reaches a predetermined temperature by heating. Specifically, when the driven body is connected to one end of the wire and the wire is heated by being energized, the wire contracts, and the displacement corresponding to the amount of the wire contraction is given to the driven body (see, for example, Patent Literature 1).